RU2546671C2 - Motor control device - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: motor control device (1) comprises: a section (6) for setting of commands of frequency for output of multiple commands of frequency; a section (5) for shaping of commands of AC voltage for formation and output of commands of AC voltage on the basis of each command of frequency; a section (4) of voltage application for the voltage application to the motor on the basis of command of AC voltage; section (3) of pre-setting of current for determination of a motor current flowing in the motor (2); and a section (7) for determination of motor type on the basis of the transfer characteristic of the motor (2) calculated on the basis of the motor current, command of AC voltage and command of frequency.

EFFECT: improvement of accuracy of determination of the motor type.

4 cl, 16 dwg

Description

FIELD OF TECHNOLOGY

The present invention relates to a control device for an engine comprising means for determining an engine type.

BACKGROUND

In order to drive a motor, such as an induction motor or a synchronous motor, it is necessary to know the type of motor in advance, before driving the motor, since the method of driving varies depending on the type of motor. Therefore, traditionally, the user recognizes the type of engine in advance and selects a control device and a control method in accordance with the type of engine. However, it can be difficult to recognize the types of some engines from their appearance. Thus, the user cannot always recognize the type of engine.

To solve the above problem, Patent Document 1 is proposed. The method according to Patent Document 1 determines the type of engine by using the fact that the degree of saturation of the engine varies depending on the type of engine.

LIST OF BIBLIOGRAPHIC REFERENCES

PATENT DOCUMENT

Patent Document 1: Japanese Patent Laid-Open Publication No. 2002-095289.

SUMMARY OF THE INVENTION

PROBLEMS THAT SHOULD BE SOLVED BY THE INVENTION

The method of Patent Document 1 determines the type of engine based on the degree of saturation of the engine. For example, in the case of an asynchronous motor, the type of motor is determined by using the fact that the degree of saturation of the motor is constant regardless of the position of the motor rotor, and in the case of a synchronous motor (synchronous motor with built-in magnet, synchronous motor with surface magnet or synchronous jet motor) determined by using the fact that the degree of saturation of the motor depends on the position of the rotor. However, in a synchronous motor designed in such a way that magnetic saturation is unlikely to occur, the change in the degree of saturation depending on the position of the rotor is small, so it can be difficult to distinguish a synchronous motor from an asynchronous motor. That is, since the degree of saturation can be influenced by the design of the engine, in addition to the type of engine, it can be difficult to determine the type of engine by a method of determining the type of engine from the degree of saturation.

The present invention was made to solve the above problem, and an object of the present invention is to provide an engine control device capable of determining an engine type by a method less susceptible to factors other than the engine type, such as engine design, thereby improving the accuracy of determination.

THE SOLUTION OF THE PROBLEM

The engine control device according to the present invention includes: a frequency command setting section for outputting a plurality of frequency commands; an AC voltage command generation section for generating and outputting an AC voltage command based on each of the frequency commands; a voltage application section for applying voltage to the engine based on an AC voltage command; a current detection section for detecting a current of the motor flowing in the engine; and a type determination section for determining a motor type based on a motor transfer characteristic calculated from a motor current, an AC voltage command and a frequency command.

SUMMARY OF THE INVENTION

The engine control device according to the present invention includes: a frequency command setting section for outputting a plurality of frequency commands; an AC voltage command generation section for generating and outputting an AC voltage command based on each of the frequency commands; a voltage application section for applying voltage to the engine based on an AC voltage command; a current detection section for detecting a current of the motor flowing in the engine; and a type determination section for determining a motor type based on a motor transfer characteristic calculated from a motor current, an AC voltage command and a frequency command. Therefore, the engine control device according to the present invention can determine an engine type based on an engine transfer characteristic less susceptible to a factor other than the engine type, such as engine design, thereby improving the accuracy of determining the engine type.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a configuration diagram according to an engine control apparatus of Embodiment 1 of the present invention.

FIG. 2 is a detailed configuration diagram according to an engine control apparatus of Embodiment 1 of the present invention.

FIG. 3 is a function explanation diagram according to an engine control apparatus of Embodiment 1 of the present invention.

FIG. 4 is a diagram for explaining functions according to an engine control apparatus of Embodiment 1 of the present invention.

FIG. 5 is a flowchart for explaining a process according to an engine control apparatus of Embodiment 1 of the present invention.

FIG. 6 is a detailed configuration diagram according to an engine control apparatus of Embodiment 1 of the present invention.

FIG. 7 is a diagram for explaining functions according to an engine control apparatus of Embodiment 1 of the present invention.

FIG. 8 is a function explanation diagram according to an engine control apparatus of Embodiment 1 of the present invention.

FIG. 9 is another configuration diagram according to an engine control apparatus of Embodiment 1 of the present invention.

FIG. 10 is another detailed configuration diagram according to an engine control apparatus of Embodiment 1 of the present invention.

FIG. 11 is a configuration diagram according to an engine control device of Embodiment 2 of the present invention.

FIG. 12 is a flowchart for explaining a process according to an engine control device of Embodiment 2 of the present invention.

FIG. 13 is a configuration diagram according to an engine control apparatus of Embodiment 2 of the present invention.

FIG. 14 is an equivalent circuit diagram of an engine according to an engine control device of Embodiment 2 of the present invention.

FIG. 15 is a detailed configuration diagram according to an engine control device of Embodiment 2 of the present invention.

DESCRIPTION OF EMBODIMENTS

Embodiment 1

Hereinafter, in the materials of the present application, Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a hardware configuration of an engine control device 1 according to Embodiment 1 of the present invention; FIG. 2 is a detailed configuration diagram, FIG. 3 and 4 are diagrams explaining functions, FIG. 5 is a flowchart for explaining a process; FIG. 6 is a detailed configuration diagram, FIG. 7 and 8 are diagrams explaining the functions. In addition, FIG. 9 and 10 are configuration diagrams showing changes according to Embodiment 1 of the present invention.

Hereinafter, in the present application, the engine control device 1 according to Embodiment 1 of the present invention will be described based on FIG. one.

In embodiment 1, the motor 2 driven by the engine control device 1 is an AC motor. The engine control device 1 includes: a voltage application section 4 for applying voltage to the engine 2; a current detection section 3 for determining a current of the motor flowing between the voltage application section 4 and the motor 2; AC voltage command generation section 5 for transmitting an AC voltage command for voltage application section 4; a frequency command setting section 6 for transmitting a frequency command f for the AC voltage command generation section 5; and a type determination section 7 for calculating an engine transfer characteristic from an AC voltage command, an engine frequency and current command, and determining a motor type.

In FIG. 1 section 3 of the current definition determines the u-phase current and v-phase current. However, any combination of two phases other than the combination of the u-phase and v-phase can be determined. Instead, the u-phase, v-phase and w-phase can be determined.

The voltage application section 4 is a semiconductor power converter and applies the AC voltage to the motor 2 based on the AC voltage command outputted by the AC voltage command generation section 5.

FIG. 2 is a detailed configuration diagram of an AC voltage command generation section 5.

Multiplier 51 multiplies the frequency command f (n) by 2π to obtain the angular frequency command ωn. The trigonometric function calculation unit 52 derives the cosine function cos (ωn · t) based on the angular frequency command ωn. Here, the trigonometric function output by the trigonometric function calculating unit 52 may be either the cosine function cos (ωn · t) or the sinusoidal function sin (ωn · t). In Embodiment 1, a case of deriving a cosine function cos (ωn · t) will be described below.

The multiplier 53 multiplies the cosine function cos (ωn · t) output by the trigonometric function calculation unit 52 by the amplitude of the voltage command Vref, which is a predetermined constant, thereby outputting Vref · cos (ωn · t). The two-phase / three-phase converter 54 performs two-phase / three-phase conversion for a voltage command along the α Vα axis and a voltage command along the β Vβ axis, which are two-axis voltage commands at rest, in accordance with expression (1), thereby outputting voltage commands AC Vu *, Vv *, and Vw *.

[Expression 1]

In embodiment 1, Vα is equal to Vref · cos (ωn · t) output by the multiplier 53, and Vβ = 0 is set. Therefore, the AC voltage command outputted by the AC voltage command generation section 5 is an alternating voltage in which the direction of the voltage vector changes between the two directions.

Note that the AC voltage command can be given, calculated by means of expression (1), using Vβ = Vref · cos (ωn · t) and Vα = 0.

In addition, Vα and Vβ can be set so as to obtain an alternating voltage in which the direction of the voltage vector varies among three or more directions. In Embodiment 1, a case of predetermined Vα and Vβ to obtain an alternating voltage will be described.

Hereinafter, as used in the present invention, an alternating voltage (current) is defined as a voltage (current) in which the voltage (current) vector changes between two directions, for example, 0 degrees and 180 degrees.

With reference to the function explanation diagram in FIG. 3, the function of the frequency command setting section 6 will be described.

The frequency command setting section 6 sets and outputs a plurality of different frequency commands. In Embodiment 1, as shown in FIG. 3, the frequency command setting section 6 sets, as the frequency command f (n), n different frequency commands from f (1) to f (n), and sequentially outputs them in accordance with the counter value n.

Next, with reference to the function explanation diagram in FIG. 4, the operation of the type determination section 7 will be described in detail.

The type determination section 7 calculates the transfer characteristic from the alternating voltage of the motor 2 to the motor current by using the motor currents iu and iv, the voltage commands AC Vu *, Vv *, and Vw *, and the frequency command f (n), and determines the motor type by means of the transfer characteristics.

Namely, the type of motor is determined depending on the motor containing the circuit (hereinafter referred to as the secondary circuit), in which current flows in the rotor, such as an induction motor or synchronous motor, and a motor that does not contain a secondary circuit, such like a permanent magnet synchronous motor or a synchronous jet engine.

FIG. 4 (a) shows an example of a transfer characteristic of an induction motor, and FIG. 4 (b) shows an example of a transfer characteristic of a permanent magnet synchronous motor. Note that the angular frequency of the horizontal axis in FIG. 4 is denoted as a decimal logarithm converted from angular frequency.

In Embodiment 1, as shown in FIG. 4, the frequency response (hereinafter referred to as the amplitude response) of the relationship (gain) between the amplitude of the alternating voltage and the amplitude of the motor current obtained by dividing the amplitude of the motor current by the amplitude of the alternating voltage is used as the transfer characteristic.

As shown in FIG. 4, the amplitude characteristic differs between a motor (asynchronous motor) containing a secondary circuit and a motor (permanent magnet motor) not containing a secondary circuit.

Namely, in the engine containing the secondary circuit shown in FIG. 4 (a), since the engine contains a secondary circuit, the transfer function of the engine is a second-order system. Therefore, there are three points (indicated by dashed circles) at which the gain slope changes on the amplitude response. On the other hand, in the secondary circuit-free motor shown in FIG. 4 (b), since its transfer function is a first-order system, there is only one point at which the gain slope changes.

Due to this feature, if there is one point at which the gain slope changes on the amplitude characteristic, the engine can be defined as an engine that does not contain a secondary circuit, and if there are two or more points at which the gain slope changes, the engine can be defined as a motor containing a secondary circuit.

Accordingly, in Embodiment 1, a gain slope is calculated, and a motor type is determined based on the gain slope.

In the future, the materials of this application will describe a specific method for determining.

FIG. 5 is a flowchart for explaining an engine type determination process according to an engine control device of Embodiment 1.

When the process starts (S51), the initial value n = 1 and the determination indicator F = 0 are set as described below (S52). Next, in accordance with the counter value n (initial value = 1), the frequency command f (n) is set (S53).

Note that the frequency command f at the counter value n is denoted by f (n), and the frequency command value corresponding to each counter value is set in advance.

Then, an alternating voltage with a frequency command f (n) is applied to the motor (S54). As described above, the alternating voltage is generated by the voltage application section 4 based on the AC voltage command output from the AC voltage command generation section 5, and then applied to the motor 2. When the alternating voltage is applied, the alternating current flows in the motor 2, and the alternating current is determined by the section 3 current definitions (S55).

Then, an alternating current amplitude indicator (S56) is calculated, and a gain G (n) is calculated, which is the ratio between the alternating current amplitude and the amplitude of the alternating voltage at the counter value n (S57). Then, the gain slope Ggd (n) is calculated (S58).

Then, the determination indicator F (S59) is calculated, described in detail later.

If the counter value n is equal to or less than the maximum counter value N_end set in advance (S60), the counter value is set to n + 1 by adding 1 to the counter value n (S61). After this, steps S53 to S60 are repeated until the counter value n becomes greater than the maximum value N_end.

If the counter value n is greater than the maximum counter value, it is determined whether the engine is a motor containing a secondary circuit or a motor not containing a secondary circuit based on the value of the determination indicator F (S62 to S64), and then the process ends (S65).

FIG. 6 is a detailed configuration diagram of a type determination section 7 in which the aforementioned calculation of the AC amplitude indicator, AC voltage amplitude Vref, gain G, and gain slope Ggd is performed, and the above motor type determination.

The current amplitude calculating unit 71 calculates and displays an alternating current amplitude indicator Iamp by means of expression (2) using the motor currents iu and iv output by the current determining section 3.

[Expression 2]

The voltage amplitude calculating unit 72 calculates the amplitude Vref of the AC voltage command by means of expression (3) using Vu *, Vv *, and Vw * output by the AC voltage command generation section 5.

[Expression 3]

The divider 73 divides the AC amplitude indicator by the amplitude Vref of the AC voltage command, thereby calculating and outputting the gain G. The delay unit 75 outputs the gain G (n-1) obtained with the counter value n-1, that is, one count before the present value counter.

The adder-subtractor 74 subtracts the gain G (n-1) one count earlier, deduced by the delay unit 75, from the gain G (n) output by the divider 73, thereby deriving the difference ΔG (n) of the gain. The multiplier 76 multiplies the frequency command f (n) output by the frequency command setting section 6 by 2π, thereby outputting the angular frequency ωn. The decimal logarithm conversion unit 77 converts the angular frequency ωn output by the multiplier 76 into the decimal logarithm of the angular frequency ωn ′ by means of expression (4).

[Expression 4]

Block 79 delay displays the value of the decimal logarithm ωn-1 'of the angular frequency obtained at the counter value n-1, that is, one count before the current counter value. The adder-subtractor 78 subtracts the value of the decimal logarithm of the angular frequency ωn-1 'earlier deduced by the delay unit 79 from the value of the decimal logarithm of the angular frequency ωn' displayed by the decimal logarithm conversion unit 77, thus outputting the difference Δωn 'of the value of the decimal logarithm angular frequency.

The divider 80 divides the difference ΔG (n) of the gain output by the adder-subtractor 74 by the difference Δωn 'of the decimal logarithm of the angular frequency output by the adder-subtractor 78, thereby calculating the slope Ggd (n) of the gain.

Next, with reference to function explanation diagrams in FIG. 7 and 8, the operation of the determination indicator calculating unit 81 in FIG. 6, that is, the calculation function of the determination indicator F (S59) of the flowchart in FIG. 5.

The determination indicator calculating unit 81 sets and outputs the determination indicator F based on the slope Ggd (n) of the gain output by the divider 80.

FIG. 7 shows an example of the gain G (n) and the slope Ggd (n) of the gain with respect to the angular frequency ωn, when an alternating voltage at frequencies f (1) through f (n) is successively applied to a motor that does not contain a secondary circuit.

FIG. 8 shows an example of the gain G (n) and the slope Ggd (n) of the gain with respect to the angular frequency ωn, when an alternating voltage at frequencies f (1) through f (n) is sequentially applied to a motor containing a secondary circuit.

As shown in FIG. 7, in an engine not containing a secondary circuit, the transfer function is a first-order system, and there is one point at which the gain slope changes on the amplitude characteristic. At low angular frequencies (from ω1 to ω6 in Fig. 7), the gain slope Ggd is close to zero. At angular frequencies (from ω7 to ω15 in Fig. 7), higher than around the point at which the gain slope changes, the higher the angular frequency, the smaller the gain slope Ggd.

On the other hand, in the engine containing the secondary circuit, in FIG. 8, the transfer function is a second-order system, and there are three points at which the gain slope changes on the amplitude characteristic. At low angular frequencies (from ω1 to ω4 in Fig. 8), the gain slope Ggd is close to zero.

Counting from the lowest frequency, in the range (from ω5 to ω8 in FIG. 8), from about the first point at which the gain slope changes, to about the second point at which the gain slope changes, the gain slope Ggd decreases. Further, in the range (from ω9 to ω12 in FIG. 8), from the second point at which the gain slope changes to about the third point at which the gain slope changes, the gain slope Ggd again increases to become close to zero. At angular frequencies (from ω13 to ω15 in Fig. 8), higher than around the third point at which the gain slope changes, the higher the angular frequency, the smaller the gain slope Ggd.

The change in the slope of the Ggd gain will be summarized as follows. In an engine that does not contain a secondary circuit, the higher the frequency, the lower the gain slope Ggd. On the other hand, in a secondary circuit containing engine, the gain slope Ggd first decreases when the frequency increases, and then the gain slope Ggd increases to become close to zero. After this, the gain slope Ggd decreases again.

The determination indicator calculating unit 81 sets and outputs the determination indicator F by using the above-described difference in the transfer characteristic.

Hereinafter, the calculation process of the determination indicator F (S59) in FIG. 5.

At the beginning of the whole process, the initial value of the determination indicator F, which should be output by the determination indicator calculation unit 81, is set to zero (S52).

While the counter value sequentially changes from 1 to n, if the gain slope Ggd (n) output by the divider 80 is less than the gain slope Ggd (n-1) one count earlier, the value Ggd (n) is stored as the minimum value Ggd_min of the gain slope, and if the slope of Ggd (n) is not less than the slope of Ggd (n-1), Ggd_min remains at its current value. In addition, at the same time that Ggd_min is set, the gain tilt threshold Glev is set.

Glev is set to Kg times from Ggd_min (Kg is the setpoint in the range 0 <Kg <1). Then, when the gain slope Ggd (n + 1) at the next counter value n + 1 is compared with the gain slope threshold Glev, if the gain slope Ggd (n + 1) is greater than the gain slope threshold Glev, 1 is added to the determination identifier F .

In an engine not containing a secondary circuit, as shown in FIG. 7, the higher the angular frequency, the lower the gain slope. Therefore, the gain slope Ggd (n + 1) never becomes greater than the threshold value Glev of the gain slope, therefore 1 is never added to the determination identifier F. That is, in the engine not containing the secondary circuit, the determination identifier F is 0.

Here in FIG. 7, the values of Ggd_min and Glev Ggd change at each point from Ggd (2) to Ggd (15), and the values of Ggd_min and Glev in the last state are shown in the graph.

On the other hand, in an engine comprising a secondary circuit, as shown in FIG. 8, since the gain slope Ggd (n + 1) becomes larger than the gain tilt threshold Glev, 1 is added to the determination identifier F. That is, in the engine containing the secondary circuit, the determination identifier F is 1.

Here in FIG. 8, the values of Ggd_min and Glev Ggd change at each point from Ggd (2) to Ggd (8), and do not change in Ggd (9) and later. The graph shows the values of Ggd_min and Glev in the last state.

Based on the value of the determination identifier F output by the determination identifier calculation unit 81, if the determination identifier F is 0, the engine type determination unit 82 determines that the engine is a secondary circuit-free motor, and if the determination identifier F is 1, determines that the engine is an engine containing a secondary circuit, thus inferring the type of engine.

In the case where the motor, as the determination target, is an asynchronous motor or a permanent magnet synchronous motor, if the determination identifier F is 0, the motor type determination unit 82 determines that the motor is a permanent magnet synchronous motor. If the determination identifier F is 1, the engine type determination unit 82 determines that the motor is an asynchronous motor. Then, the engine type determination unit 82 outputs the engine type.

As described above, in embodiment 1, the voltage amplitude calculating unit 72 in FIG. 6 calculated the amplitude Vref of the AC voltage command by expressing (3) from Vu *, Vv * and Vw * output by the AC voltage command generation section 5. However, instead of calculating the amplitude of the AC voltage by means of expression (3), Vref can be obtained directly from AC command generation section 5 in FIG. 1. In this case, the voltage amplitude calculation unit 72 is not needed.

FIG. 9 shows a configuration diagram of an engine control device in a case where Vref is obtained directly from AC voltage generating section 5.

In addition, in Embodiment 1, a frequency command f (n) for each counter value n is set in advance in accordance with the counter value n. However, the decimal logarithm of the angular frequency can change at regular intervals in accordance with the counter values. In this case, since Δωn 'is constant, the gain slope Ggd (n) is simply proportional only to the difference ΔG (n) of the gain.

To determine the type of engine, the absolute value of the gain slope Ggd (n) is not required, but it is only necessary to obtain a point at which the gain slope changes.

Therefore, as shown in FIG. 10, if the gain difference ΔG (n) is specified as the gain slope Ggd (n), the calculation of the difference in the value of the decimal logarithm of the angular frequency can be omitted. As a result, the configuration of the engine control device type determination section 7 shown in FIG. 6 can be simplified as the configuration of the type determination section 107 shown in FIG. 10.

Note that in section 107, the definition of the type Vref is obtained directly from section 5 of the formation of AC voltage commands.

Thus, according to Embodiment 1, the engine control device 1 determines the type of engine based on the transfer characteristic of the engine 2. The engine control device 1 calculates, as the transfer characteristic of the engine 2, the gain G, which is the frequency response of the relationship between the amplitude of the alternating voltage and the current amplitude motor, and then obtains the gain slope Ggd from the calculated gain G.

Therefore, since the engine control device 1 according to Embodiment 1 determines whether the engine is a secondary circuit-free engine or a secondary circuit engine without using magnetic saturation of the engine, the engine control device 1 provides an effect of improving detection accuracy.

Embodiment 2

Hereinafter, in the materials of this application, embodiment 2 of the present invention will be described based on the drawings. FIG. 11 is a diagram showing a hardware configuration of an engine control apparatus 201 according to Embodiment 2 of the present invention; FIG. 12 is a flowchart for explaining a process; FIG. 13 is a configuration diagram of FIG. 14 is an equivalent circuit of the engine, FIG. 15 is a detailed configuration diagram. In FIG. 11 components that match or correspond to the components of FIG. 1 are denoted by the same conventions.

In Embodiment 2, the engine constant is calculated as the transfer characteristic of the engine, and a determination of the engine type as to whether the engine is a secondary circuit-containing engine or a secondary circuit-free engine is performed based on the motor constant.

The configuration of the engine control apparatus 201 according to Embodiment 2 of the present invention shown in FIG. 11 differs only in type determination section 207 compared to the configuration diagram of Embodiment 1 shown in FIG. 1, and other parts are the same as in FIG. 1. Accordingly, the configuration and operation of only the type determination section 207 will be described.

Section 207 type determination calculates the constant of the engine of the engine 2 by assuming that the engine 2 is a motor containing a secondary circuit.

In the case of a motor containing a secondary circuit, as a result of calculating the motor constant, all motor constants become positive real numbers. However, in the case of a motor that does not contain a secondary circuit, due to the absence of a secondary circuit, the motor constants related to the secondary circuit, such as the resistance of the secondary winding, the inductance of the secondary winding, and the mutual inductance between the inductance of the primary winding and the inductance of the secondary winding become values (negative or imaginary number) other than positive real numbers. By using the above feature, it is determined whether the engine is an engine containing a secondary circuit or an engine not containing a secondary circuit.

FIG. 12 is a flowchart for determining an engine type according to Embodiment 2.

When the process starts (S101), the initial value n = 1 is set (S102). Next, in accordance with the counter value n (initial value = 1), the frequency command f (n) is set (S103).

Then, an alternating voltage is applied to the frequency command f (n) (S104), and an alternating current having the same frequency as the alternating voltage is determined from the current of the motor current in the motor 2 (S105).

In order to obtain a constant of a motor containing a secondary circuit, by assuming that motor 2 is a motor containing a secondary circuit, a common mode current having the same phase direction as an alternating voltage, and a current with a quadrature phase having a quadrature phase direction with respect to the alternating voltage, removed from the alternating current, and then stored (S106).

If the counter value n is equal to or less than the maximum counter value N_end set in advance (S107), the counter value is set to n + 1 by adding 1 to the counter value n (S108). After that, steps S103 to S106 are repeated until the value of counter n becomes greater than the maximum value of counter N_end.

If the counter value n is greater than the maximum counter value, the transfer function Gim (s) is determined based on the stored common-mode currents and quadrature currents by assuming that motor 2 is a motor containing a secondary circuit (S109).

Next, from the specific transfer function Gim (s), the engine constants are calculated, i.e. the resistance Rs of the primary winding, the resistance Rr of the secondary winding, the inductance Ls of the primary winding, the inductance Lr of the secondary winding and the mutual inductance M (S110).

In the case where the motor 2 is a secondary circuit-free motor, among the calculated motor constants, the secondary resistance Rr and the mutual inductance M, which are the motor constants related to the secondary circuit, become values other than a positive real number. Therefore, if the resistance Rr of the secondary winding and the mutual inductance M are positive real numbers, motor 2 is defined as a motor containing a secondary circuit, and if they are not positive real numbers, motor 2 is defined as a motor not containing a secondary circuit.

Note that the inductance Lr of the secondary winding is also a motor constant related to the secondary circuit. However, since the calculations assume the inductance Ls of the primary winding = the inductance Lr of the secondary winding, the inductance Lr of the secondary winding becomes a positive real number even in an engine that does not contain a secondary circuit, as a result of calculating the motor constant. Therefore, only the secondary resistance Rr and the mutual inductance M are used to determine the type of motor.

Hereinafter, the block diagram of the sequence of operations in FIG. 12.

In the process from setting the frequency command f (n) (S103) to determining the alternating current (S105) in FIG. 12, as in embodiment 1, the frequency command setting section 6 sets the frequency command f (n) in accordance with the counter value n (initial value = 1). The AC voltage command generation section 5 performs two-phase / three-phase conversion for the α-axis voltage command Vα = Vref · cos (ωn · t) and the β-voltage command on the β axis Vβ = 0 on two axes at rest by means of expression (1), thereby forming AC voltage command. Based on the AC voltage command, the voltage application section 4 applies an alternating voltage to the motor 2. Then, the current determination section 3 determines the motor currents iu and iv.

The determination (S105) of the alternating current and the subsequent steps in the flowchart of FIG. 12 correspond to the processing by the type determination section 207 in FIG. 11 of embodiment 2.

FIG. 13 is a configuration diagram of a type determination section 207, and FIG. 15 shows a detailed configuration diagram of an engine constant calculation section 270 of a type determination section 207.

The process from determining the alternating current (S105) to calculating the motor constant (S110) in the flowchart of FIG. 12 is a process for calculating motor constants by assuming that motor 2 is a motor containing a secondary circuit. This process corresponds to the motor constant calculation section 270 of FIG. 13. At step 111, it is determined whether or not the secondary resistance Rr and the mutual inductance M are positive real numbers.

First, the engine constant calculation section 270 of the type determination section 207 will be described.

FIG. 14 is an equivalent circuit for a single phase of an induction motor, which is a motor containing a secondary circuit, in a stopped state. From FIG. 14, the transfer function Gim (s) from the input voltage Vs to the output current can be represented by expression (5). Using the coefficients a ₁ , a ₂ , b ₀ and b ₁ , expression (5) can be represented by expression (6).

[Expression 5]

[Expression 6]

Note that the symbols in FIG. 14 and in expressions (5) and (6) denote the following:

M: mutual inductance, ls: primary leakage inductance, lr: secondary leakage inductance

Rs: primary resistance, Ls: primary inductance (= ls + M)

Rr: secondary resistance, Lr: secondary inductance (= lr + M)

s: Laplace operator

In order to calculate the engine constant by assuming that the engine 2 is an engine containing a secondary circuit, the engine constant calculation section 270 determines the transfer function Gim (s) of the engine containing the secondary circuit represented by expression (6), thereby obtaining coefficients a ₁ , a ₂ , b ₀ and b ₁ . From the obtained coefficients a ₁ , a ₂ , b ₀ and b ₁ , the engine constants are calculated using expressions (7) through (10).

Note that typically the inductance Ls of the primary winding and the inductance Lr of the secondary winding are close to each other. Therefore, Ls = Lr is assumed when calculating the motor constants from the coefficients a ₁ , a ₂ , b ₀ and b ₁ .

[Expression 7]

[Expression 8]

[Expression 9]

[Expression 10]

FIG. 15 is a detailed configuration diagram of a motor constant calculation section 270, which consists of a part for calculating and storing common mode current and quadrature phase current, and a part for determining a transfer function.

The alternating voltage described above is applied based on Vα = Vref · cos (ωn · t) and Vβ = 0, and the current determination section 3 determines the motor current. Certain motor currents iu and iv are converted to current along the α axis and to current along the β axis on two axes at rest by means of expression (11). If the converted current along the α axis is denoted by iα, and the converted current along the β axis is denoted by iβ, iα and iβ can be represented by expression (12). Note that in expression (12), Iα is the amplitude of the current along the α axis, and φ is the phase shift between Vα and iα.

[Expression 11]

[Expression 12]

If the transfer function from Vα to iα is designated as Gα (jωn), the transfer function Gα (jωn) can be represented by expression (13) when an alternating voltage Vα = Vref · cos (ωn · t) is applied.

[Expression 13]

In expression (13), | Iα / Vref | cosφ is indicated as a common-mode current, and | Iα / Vref | sinφ is indicated as a current with a quadrature phase. In the part for calculating and storing common mode current and quadrature phase current in FIG. 15, the aforementioned common mode current and quadrature phase current are calculated.

In expression (13), since Vref is a known quantity, the transfer function Gα (jωn) can be obtained by calculating the in-phase current | Iα | cosφ and the current with the quadrature phase | Iα | sinφ.

Next, a method for calculating the common mode current | Iα | cosφ and the quadrature current | Iα | sinφ will be described. The cosine function 2cos (ωn · t) and the sinusoidal function 2sin (ωn · t) are prepared, and then the values obtained by multiplying iα by the cosine function and the sinusoidal function are denoted by ξr and ξi, respectively. Then ξr and ξi are represented by expressions (14) and (15), respectively.

[Expression 14]

[Expression 15]

As is evident from expressions (14) and (15), ξr and ξi consist of the component AC, which has an angular frequency of 2ωn, and the components DC | Iα | · cosφ or | Iα | · sinφ. Therefore, by removing the component of the angular frequency 2ωn from ξr and ξi, the in-phase current | Iα | cosφ and the quadrature current | Iα | sinφ can be obtained.

In Embodiment 2, in order to remove the angular frequency component 2ωn from ξr and ξi, a notch filter represented by expression (16) is applied, thereby obtaining a common mode current | Iα | cosφ and a quadrature current | Iα | sinφ, as shown by the expressions ( 17) and (18).

Here, a notch filter is used only to extract the necessary signal. Namely, the notch filter is a filter that makes the gain for the narrowband signal frequency equal to 0, and makes the gain of other frequencies equal to 1.

Note that the common-mode current | Iα | cosφ and the quadrature phase current | Iα | sinφ for a counter n are denoted by Ire (n) and Iim (n), respectively.

[Expression 16]

[Expression 17]

[Expression 18]

Thus, in order to calculate Ire (n) and Iim (n) in the part for calculating and storing common mode current and quadrature phase current in FIG. 15, a three-phase / two-phase converter 711 converts iu and iv, determined by the current detection section 3, into iα and iβ.

The multiplier 712 multiplies the frequency command f (n) with the counter value n output by the frequency command setting section 6 by 2π, thereby outputting the angular frequency command for ωn. A cosine function calculation unit 713 outputs a cosine function cosωnt with an angular frequency ωn, and a sinusoid function calculation unit 714 outputs a sinusoid function sinωnt with an angular frequency ωn.

The proportional units 715 and 716 double the cosine function cosωnt output by the cosine function calculation unit 713 and the sinusoid function sinωnt output by the sinusoid function calculation unit 714, thereby outputting 2cosωnt and 2sinωnt, respectively. Multipliers 717 and 718 multiply 2cosωnt and 2sinωnt, output by the proportional units 715 and 716, by iα, output by the three-phase / two-phase converter 711, thereby outputting ξr and ξi in expressions (14) and (15), respectively.

Notch filters 719 and 720 apply notch filters to ξr and ξi output by multipliers 717 and 718, respectively, thereby outputting the common mode current Ire (n) and the current with quadrature phase Iim (n) in expressions (17) and (18) at counter n, respectively.

In addition, if the counter value n is equal to or less than N_end, the common mode current storage unit 721 stores the common mode current Ire (n). If the counter value n becomes larger than N_end, the common mode current storage unit 712 outputs the stored common mode currents from Ire (1) to Ire (N_end) as the stored common mode current values.

If the counter value n is equal to or less than N_end, the quadrature phase current storage unit 722 stores the quadrature phase current Iim (n). If the counter value n becomes larger than N_end, the quadrature phase current storage unit 722 outputs stored quadrature phase currents from Iim (1) to Iim (N_end) as stored quadrature phase current values.

If the counter value n is equal to or less than N_end, the angular frequency storage unit 723 stores the angular frequency ωn at the counter value n. If the counter value n becomes larger than N_end, the angular frequency storage unit 723 outputs the angular frequencies ω1 to ωN_end as the stored angular frequency values.

Next, a transfer function determination unit 725 will be described. When an alternating voltage Vα = Vref · cos (ωn · t) having an angular frequency ωn is applied, the transfer function from Vα to iα can be represented by expression (19) using the above-described common mode current Ire (n) and the current with a quadrature phase Iim (n ) Here, the transfer function in expression (19) is denoted by H (jωn).

[Expression 19]

In addition, if the denominator and numerator of the transfer function Gim (s) of the engine containing the secondary circuit in the expression (5) are designated as A (s) and B (s), and determined by the expressions (20) and (21), respectively, Gim (s) is represented by the expression (22). In addition, if the Laplace operator s in expression (22) is replaced by jωn, expression (22) can be represented by expression (23).

[Expression 20]

[Expression 21]

[Expression 22]

[Expression 23]

As described above, in Embodiment 2, since the engine constants are calculated by assuming that the engine 2 is an engine containing a secondary circuit, the transfer function H (jωn) in expression (19) is assumed to be equal to the transfer function Gim (jωn) of the engine containing the secondary chain, in the expression (23). That is, we get the connection shown by expression (24).

[Expression 24]

Here, ε (n) is defined by expression (25). From expression (24), ideally, ε (n) in expression (25) becomes zero. Then, using the least squares method, unknown coefficients a1, a2, b0 and b1 are calculated to minimize expression (26).

[Expression 25]

[Expression 26]

Next, a method for obtaining expression (26) will be described.

If ε is determined by expression (27), there is a relation shown by expression (28) between ε and εT, which is the transposed matrix ε.

[Expression 27]

[Expression 28]

Here, if ε 'is defined by expression (29), the function of expression (26) can be obtained from expressions (28) and (29), as shown by expression (30).

[Expression 29]

[Expression 30]

When N_end> 2, coefficients a1, a2, b0, and b1 that minimize expression (30) can be obtained by applying the least squares method, as shown by expression (31).

[Expression 31]

If the counter value has become larger than N_end, as described above, the transmission function determination unit 725 in FIG. 15 calculates expressions (19) and (29) - (31) by using the stored common-mode current values and the stored quadrature phase current values output by the common-mode current storage unit 721 and the stored angular frequency values output by the angular frequency storage unit 723, thereby obtaining the coefficients a1, a2, b0 and b1.

Note that, as Vref in expression (19), Vref is used, calculated from expression (3) by voltage amplitude calculation unit 724.

In addition, as described in Embodiment 1, Vref can be obtained directly from AC voltage command generation section 5 in FIG. 11. In this case, the voltage amplitude calculation unit 724 is not needed.

The motor constant conversion unit 726 calculates the motor constants, i.e., the primary winding resistance Rs, the secondary winding resistance Rr, the primary winding inductance Ls (= the secondary winding inductance Lr), and the mutual inductance M from the coefficients a1, a2, b0 and b1 output by the unit 725 determine the transfer function by using expressions (7) - (10). From these values, the motor constant conversion unit 726 outputs the secondary resistance Rr and the mutual inductance M to use them to determine the type of motor.

The engine constant calculation section 270 of FIG. 13 outputs to the motor type determination unit 271 the secondary resistance Rr and the mutual inductance M output by the motor constant conversion unit 726.

The engine type determination unit 271 in FIG. 13 determines the type of motor from the resistance Rr of the secondary winding and the mutual inductance M output by the motor constant calculation section 270.

If both the resistance Rr of the secondary winding and the mutual inductance M are positive real numbers, the engine type determination unit 271 determines the engine as an engine containing a secondary circuit, and if both values are not positive material numbers, the engine type determination unit 271 determines the engine as an engine containing no secondary circuit. Then, the engine type determination unit 271 outputs a specific engine type.

Note that in the case when the motor 2 is an asynchronous motor or a permanent magnet synchronous motor, if both the secondary resistance Rr and the mutual inductance M are positive real numbers, motor 2 can be defined as an asynchronous motor, and if not, motor 2 can be defined as a permanent magnet synchronous motor.

As described above, the engine control device 201 according to Embodiment 2 calculates the engine constants as the transfer characteristic of the engine 2 and determines the engine type from the engine constants.

The engine control device 201 applies an alternating voltage set on the basis of many different frequency commands to the motor 2, and then determines the transfer function of the motor 2 from the alternating current flowing in the motor 2 and the alternating voltage by assuming that the motor 2 is a motor containing a secondary chain. From the determined transfer function, the engine control device 201 calculates the engine constants as the transfer characteristics of the engine 2. From the calculated engine constants, if both the secondary resistance Rr and the mutual inductance M are positive real numbers, the engine control device 201 determines the engine as an engine containing the secondary circuit, and if not, defines the engine as an engine that does not contain a secondary circuit. Therefore, since the engine control device 201 according to Embodiment 2 determines whether the engine is a secondary circuit engine or a secondary circuit engine without using magnetic saturation of the engine, the engine control device 201 provides an effect of improving detection accuracy.

INDUSTRIAL APPLICABILITY

The present invention relates to a control device for an engine, and more particularly, to a control device for an engine comprising means for determining a type of engine that is a control objective by using an engine transfer characteristic, and is widely applicable to a control device for an AC engine.

Claims (4)

1. An engine control device comprising:
a frequency command setting section for sequentially outputting n frequency commands having different frequencies;
an AC voltage command generation section for generating and outputting n AC voltage commands based on n frequency commands;
a voltage application section for applying AC voltage to the motor based on n AC voltage commands;
a current determination section for determining n motor currents flowing in the motor in response to n AC voltage commands; and
a type determination section for determining an engine type, wherein
the type determination section calculates the relationship between the amplitude of the motor current and the amplitude of the AC voltage command according to each of the n frequency commands and determines the motor type based on a change in relation to n frequency commands. 2. The engine control device according to claim 1, wherein the type determination section
calculates the gain slope based on: the kth value of the frequency command f (k) (2≤k≤n) sequentially output by the frequency command setting section; the relationship between the amplitude of the motor current and the amplitude of the voltage command AC received when the value of the frequency command f (k) is set; the (k-1) th value of the frequency command f (k-1) sequentially output by the frequency command setting section; and the relationship between the amplitude of the motor current and the amplitude of the voltage command AC obtained when
set the value of the frequency command f (k-1),
gets the point at which the gain slope changes, and
determines the type of engine based on the number of gain slope points. 3. The engine control device according to claim 1, wherein the type determination section identifies the transfer function of the motor from the amplitudes n of the motor currents and the amplitudes n of the AC voltage commands according to n frequency commands, and determines the type of motor based on the motor constant calculated from the transfer function. 4. The engine control device according to claim 3, wherein the transfer function is identified by assuming that the engine contains a secondary circuit, and the type determination section determines the type of motor from the secondary resistance and mutual inductance, which are the motor constants calculated from the transfer function.

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